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Round Narrowest in Middle of Brass

Discussion in 'Reloading' started by modelflyer2003, Apr 3, 2010.

  1. modelflyer2003

    modelflyer2003

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    New to reloading and I made an observation. I have everything I need now except the FMJ 9mm bullets and they are on their way. I do have some <?xml:namespace prefix = st1 ns = "urn:schemas-microsoft-com:eek:ffice:smarttags" /><st1:State w:st="on"><st1:place w:st="on">Berry</st1:place></st1:State> plated rounds that I am using to set the dies and get the process down while I wait for the FMJ to be delivered. People have said they have had some problems with keyholing with Glocks while others say they work fine for them (This post isn’t really about that though). I figured I would start out reloading without the unknown factor added in. I made four or so dummy rounds to get the dies set I used the calipers to match the OAL to the UMC 9mm store bought (Dunham’s) so I know the length will work in my Glock 26 and Beretta 92FS Compact. In fact they all chamber and eject from both guns. When I looked closely at the cases I noticed that the cases were wider at the ends than in the middle. Here are the caliper measurements from a dummy round:
    <?xml:namespace prefix = o ns = "urn:schemas-microsoft-com:eek:ffice:eek:ffice" /><o:p> </o:p>
    Dummy Round
    Widest near the head = .386
    Narrowest part of body = .374 (1/3 from the mouth of brass)
    Nearest to end of brass = .377
    <o:p> </o:p>
    UMC 9mm Store bought
    Widest near head = .385
    Measured where dummy round was narrowest = .378
    Nearest to end of brass = .375
    <o:p> </o:p>
    I know that the <st1:State w:st="on"><st1:place w:st="on">Berry</st1:place></st1:State>’s plated rounds state that the wide of the 115 gr RN is .356. The Lyman 49<SUP>th</SUP> Ed says that the width should be .355. Is this enough difference to cause trouble and is the case narrowing a problem? Thanks.
     
  2. GlockPride

    GlockPride Glock 23

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    Yep, I always thought lead in .356 was ok, but .355 for copper jacketed was needed. Not sure as I have not been reloading 9x19 for very long.
    I wouldn't worry about the width of the cases if the feed but more closely watch the OALength as too short can cause pressure spikes and too long can cause failure to feed.
     

  3. RustySocket

    RustySocket

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    Berrys are plated not jacketed... they shoot like lead.

    To the OP, what your seeing is known as coke bottle. I wouldn't worry about it.

    Ive shot tens of thousands of them, berrys work fine.
     
    Last edited: Apr 3, 2010
  4. HAMMERHEAD

    HAMMERHEAD

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    It should not be a problem. Rainier's plated .356" 130 grain RN is my standard bullet for 9mm, no problems in Glocks or 9mm carbines.
    Your sizer die is squeezing a little more than the factory brass was squezed. Make sure you are flaring just enough to ease the bullets start into the case. Too much flair will cause a bulging ring just below the crimp, and measure more than it should.
     
  5. rg1

    rg1

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    A 9MM factory case has a tapered outside. If you bought a steel sizing die it has this taper built in to the die. Since most 9MM sizing dies are now carbide, they have a carbide ring and this ring does not have a full taper built in. It sizes the case more like a straight sided case. Since it sizes the tapered case wall straight down, it takes the taper out of the case leaving the area near the case head larger. When the bullet seats it swells the mouth area and you as a result have a smaller diameter below where the bullet stops and the larger case head.
     
  6. Zombie Steve

    Zombie Steve Decap Pin Killa

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    I'm more worried about the rounds that come out without a slight hourglass shape.